Rectifier



.my 2l, w31. I H- PDONLE'" 1,815,370 RECTIFIER Original Filed June 29, 1925 INVENTOR Haz-OLII?. onle,

Patented July 21, 1931 UNITED STATES PATENT OFFICE HAROLD P. DONLE, OF MERIDEN, CONNECTICUT, ASSIGNOR TO RADIO INVENTIONS, INC., OF NEW YORK, N. Y., A CORPORATION OF NEW YORK RECTIFIER Original application led .Tune 29, 1925, Serial No. 40,414. Divided and this application led September 17, 1927. Serial No. 220,153.

My invention relates to devices for rectifyinfr alternating current. One object is to provi e a simple and reliable device which can be used for supplying direct current to radio receiving outfits. Another object is to provide a rectifying device which is comparatively small and light in Weight and yet rugged and durable.

Another object is to provide a device of this character which is efficient and reliable.

Another object is to provide a rectifier which will operate with uniformity under varying conditions.

Another object is due to overheating.

Another object is toprovide a satisfactory form of full wave rectifier.

In the preferred form of device I employ two anodes arranged in proximity to each other and surrounded by a common cathode, the effective operating surface of the cathode being of much larger area than the area of either anode. These electrodes are mounted within a container or envelope which has been partially evacuated so that the pressure is suitable for ionization but without destruction of the electrodes. The electrodes are supported in such a manner as to maintain proper electrical insulation and give the tube the maximum practical life.

Fig. 1 is a perspective view of one form of device parts being broken away for exhibition purposes.

Fig. 2 is a. transverse sectional view of the tube showing the electrodes in plan.

Fig. 3 is a framentary side view of a modification.

Fig. 4 is a side view and partial section showing a rectifier tube with the reinforcing and protecting device of Fig. 3.

The anodes 10 and 11 are mounted side by side within the cathode 12 whose inner wall constitutes the active effective surface surrounding the anodes. These electrodes may be of any suitable material. I have found that the anodes may conveniently be of steel or nickel and the cathode of nickel although the invention is not limited to the use of such materials. The cathode is spaced apart a to prevent deterioration sufficient distance from the anodes to permit ionization to occur.

The enclosing vessel or envelope 13 is preferably of glass in a form commonly referred to as a tube suitably constructed to maintain a low internal pressure. For convenience in construction and operation this tube has an interior stem 14 sometimes referred to as a press which supports the conductors 15, 16 and 17 and any other supporting Wire or rod 18 which may be desirable.

In this case the anodes 10 and 11 are mounted on the outer ends of the conductors 15 and 16 respectively, the anodes being provided With longitudinal passages so that they may conveniently be slipped over the ends of the conductors in the process of assembly.

The cathode 12 is suitably secured to the supporting members or brackets 17 and 18, for instance by welding.

Each of the anodes in this form is tubular and provided With discs 2O and 21 in its ends to fit a conducting support. The plate`23 for instance of nickel is supported on brackets 24 whose ends are sealed in the press or stem 14. This plate is provided with collars 25 which extend up around the lower ends of the anodes but spaced apart from the anodes. This plate and collars serve to shield the conductors below the anodes and around the press or stem. In case the bracket 17 or 18 contacts with the plate 23 the latter serves as a part of the cathode structure. In any event it serves as a heat radiating surface.

In Fig. 3 I have shown an insulating body 26 of lava or the like formed around the lower ends of the conductors 15, 16, 17 adjacent the stem. This block may be provided with individual extensions 27 around each conductor.

I have shown the device of Fig. 1 associated with a circuit indicating diagrammatically the source 30 of alternating current and a transformer having coils 31 and 32 and a work circuit 33. The electrodes of the tube are connected to the transformer and to the work circuit so as to produce What is commonly referred to as full Wave rectification.

In manufacturing this device the electrodes andthe insulating and radiating members are assembled on the stem and inserted within the tube which is pumped hard and baked so as to drive out all the moisture and gases practical. A small amount of material such as magnesium may be placed in the tube to keep the conditions constant when in operation. When the tube has been pumped and baked it is heated suiiiciently to evaporate a small quantity of this material. The pump is then closed and some form of inert gas such as argon, neon, etc., is admitted until the pressure reaches the desired amount. I have found a pressure in the neighborhood of 3 millimeters of mercury quite satisfactory in a tube of the characteristics herein shown and described. The pressure may be less or greater than this but I have found the voperation not satisfactor when the pressure in this particular tube is less than .6 millimeter or greater than 3.5 millimeters. After the gas has been admitted the tube is again heated for instance in an induction furnace so as to bring the electrodes up to a white heat. The tube shown is suitable for operation on a 220 volt circuit and will produce satisfactory direct current for use in a radio receiving set. Some tubes of this general type operate fairly well at a pressure of 6 millimeters.

In this form of device embodying the two anodes arranged within a common cathode I find a much greater uniformity and efficiency of operation than is possible with two separate half wave rectltiers. There seems to be some cooperation between the anodes which is interfered with if the anodes are shielded from each other. The operation appears to depend upon having the cathode area immediately adjacent the anodes considerably greater than the area of the anodes.

While I have indicated quite definite limits of gas pressure I wish it understood that these limits apply to the particular devices herein shown and described and while I believe that these pressures should not be materially departed from with devices Operating at comparatively low voltages I believe that with other mechanical constructions and under other conditions of operation that there may be considerable variation in the operating gas pressure of the tube. The claims therefore are to be construed according to their terms and they are not limited to the conditions herein set forth except as they may specify such conditions or as may be required by the prior art.

This application is a division of my application #40,414 filed June 29, 1925, and contains matter divided out of that application on which earlier application the invention herein set forth is more broadly claimed and which application contains claims to another species of the broad invention.

I claim:

1. A full wave rectifier comprising a tube having a stem with conductors sealed therein, anodes extending from conductors, a plate positioned by another conductor, a cathode surrounding the tips of said anodes and supported on another of said conductors and tubes supported by said plate and surrounding the bases of the anodes between the cathode and the anodes.

2. A rectifier comprising a tube having a stem with three conductors sealed therein, anodes carried by two of said conductors, a metallic disc mounted on said stem and a cathode supported by the third conductor and surrounding the tips of the anodes but leaving a free space between the anodes.

3. A rectifier tube comprising a stem, an anode having a conductor sealed in said stem', a cathode cylinder surrounding said anode, a metallic disc surrounding said anode conductor below said cylinder, a tubular projection on said disc surrounding a part of said anode and a heat resisting member interposed between the anode and the stem.

4. A rectifier comprising a tube having two anode Wires and two cathode wires sealed therein, a single insulator on each of the two anode wires adjacent said sealed portions, anodes supported on said anode wires, a cathode supported on the two cathode wires and surrounding said anodes and a plate below said cathode and above said insulator around said anode wires.

5. A rectifier comprising a tube having an internal press, two anodes spaced apart from each other, a cathode having a wall surrounding parts of the anodes, lead-in wires supported in the press and connected to the anodes and the cathode respectively, a mass of insulation and a metallic shield surrounding the wires at the base of the anodes between the cathode wall and the press, the space between the active portions of the anodes being free of obstruction.

6. A rectifier comprising a tube having a stem at one end, a cathode lead and two anode leads sealed in said stem, a hollow cathode supported by said stem and electrically connected to the cathode lead and having one end presented toward said stem, anodes connected to said anode leads and supported with their tips projecting into one end of the cathode, a plate supported by said stem and having openings for the anodes, and shielding collars surrounding but spaced apart from parts of the anodes, the space between said anodes within said cathode being unobstructed.

HAROLD P. DONLE. 

